Frequency of subclinical thyroid dysfunction and risk factors for cardiovascular disease among women at a workplace

Subclinical thyroid dysfunction is very common in clinical practice and there is some evidence that it may be associated with cardiovascular disease. The aim here was to evaluate the frequencies of subclinical thyroid disease and risk factors for cardiovascular disease among women at a workplace, and to evaluate the association between subclinical thyroid disease and cardiovascular risk factors among them.

Cross-sectional study on 314 women aged 40 years or over who were working at Universidade de São Paulo (USP).

All the women answered a questionnaire on sociodemographic characteristics and risk factors for cardiovascular disease and the Rose angina questionnaire. Anthropometric variables were measured and blood samples were analyzed for blood glucose, total cholesterol and fractions, high-sensitivity C-reactive protein, thyroid-stimulating hormone (TSH), free thyroxine (free-T4) and anti-thyroperoxidase antibodies (anti-TPO).

The frequencies of subclinical hypothyroidism and hyperthyroidism were, respectively, 7.3% and 5.1%. Women with subclinical thyroid disease presented higher levels of anti-TPO than did women with normal thyroid function (P = 0.01). There were no differences in sociodemographic factors and cardiovascular risk factors according to thyroid function status, except for greater sedentarism among the women with subclinical hypothyroidism. Restricting the comparison to women with subclinical hypothyroidism (TSH > 10 mIU/l) did not change the results.

In this sample of women, there was no association between poor profile of cardiovascular risk factors and presence of subclinical thyroid disease that would justify screening at the workplace.